Region-specific astrogliosis in brains of mice heterozygous for mutations in the neurofibromatosis type 1 (Nf1) tumor suppressor

Brains from human neurofibromatosis type 1 (NF1) patients show increased expression of glial fibrillary acidic protein (GFAP), consistent with activation of astrocytes (M.L. Nordlund, T.A. Rizvi, C.I. Brannan, N. Ratner, Neurofibromin expression and astrogliosis in neurofibromatosis (type 1) brains, J. Neuropathol. Exp. Neurology 54 (1995) 588-600). We analyzed brains from transgenic mice in which the Nf1 gene was targeted by homologous recombination. We show here that, in all heterozygous mice analyzed, there are increased numbers of astrocytes expressing high levels of GFAP in medial regions of the periaqueductal gray and in the nucleus accumbens. More subtle, but significant, changes in the number of GFAP positive astrocytes were observed in the hippocampus in 60% of mutant mice analyzed. Astrocytes with elevated GFAP were present at 1 month, 2 months, 6 months and 12 months after birth. Most brain regions, including the cerebellum, basal ganglia, cerebral cortex, hypothalamus, thalamus, cortical amygdaloid area, and white matter tracts did not show any gliotic changes. No evidence of degenerating neurons was found using de Olmos' cupric silver stain. We conclude that Nf1/nf1 mice provide a model to study astrogliosis associated with neurofibromatosis type 1.     

Region-specific DNA synthesis in brains of F344 rats following a six-day bromodeoxyuridine infusion

Prolonged exposure to certain alkylating chemicals induces glial and meningeal tumours in rats, probably resulting from DNA damage to dividing neural cells. The present work evaluated DNA synthesis in the brains of untreated, young adult male F344 rats in order to define a BrdUrd infusion protocol to more adequately assess proliferation in slowly dividing neural cell populations. BrdUrd (2.5 to 160 mg/ml) was administered for 6 days via subcutaneous osmotic pumps. Clinical toxicity was not observed at any dose. The labelling index (LI; % of cells per brain area that incorporated BrdUrd) and unit length labelling index (ULLI; % of cells per meningeal length that incorporated BrdUrd) were calculated for selected regions by counting labelled neural cells in defined areas of the right hemisphere in coronal brain sections. Intensely stained cells were numerous in the cerebral subependymal layer (LI = 35.8%); scattered in cerebral white matter tracts (e.g. corpus callosum and internal capsule; LI = 6.2%) as well as cerebral (ULLI = 4.2%) and cerebellar (ULLI = 3.6%) meninges; and rare in the hippocampus (LI > 0.1%). Mildy stained cells were dispersed in the pons (LI = 2.1%), deep cerebral (LI = 1.8%) and cerebellar (LI = 1.0%) grey matter, and thalamus (LI = 0.3%). Phenotypically, BrdUrd-positive cells in neuropil were glial cell precursors and their progeny, while those associated with meninges were usually located in the superficial subarachnoid space and appeared to be fibrocytes. Using BrdUrd infusion, LI for glial precursors at these sites ranged from two- to 10-fold higher than those reported previously after a brief parenteral pulse dose. These data indicate that continuous BrdUrd infusion for 6 days by subcutaneous osmotic pump is an efficient means of labelling neural cells throughout the brain.     

In vivo release of dopamine and its metabolites from rat striatum in response to domoic acid

The microdialysis technique was used to examine the effect of the neurotoxin domoate, an analog of glutamic acid, on striatal dopamine activity. Our results show that the intracerebral administration of different concentrations of domoate (100 and 500 microM) produced increases in the extracellular levels of dopamine associated to decreases in the extracellular levels of its metabolites dihydroxyphenylacetate and homovanillate from rat striatum. These changes seem to be related according to a time sequence, indicating a possible effect on the metabolism of dopamine. Changes were also observed in locomotor activity (cycling behavior, sniffing around and chewing) in rats during the domoate infusion. The physiological mechanism by which domoate increased dopamine release remains to be worked out.     

Therapeutic suggestions given during neurolept-anaesthesia decrease post-operative nausea and vomiting

BACKGROUND: Data on prevalence of cigarette smoking by hospital employees are limited in Australia, but anecdotal evidence suggests that many health sector employees continue to smoke despite abundant evidence regarding the harmful effects of this habit. Nicotine is an addictive drug and arguably this should be known better in the health industry than in any other industry. Despite having this knowledge at their disposal, health sector employers rarely provide assistance to employees, relying instead on restrictive policies to reduce smoking in the workplace. METHODS: To assist employees to quit smoking, we instituted a medium intensity Stop Smoking Programme, run by a clinical pharmacist offering nicotine patches and support on a weekly basis. A principal aim of the service was to redress the imbalance between the availability of cigarettes and the most effective nicotine replacement therapy, the trandermal nicotine patch. Following 18 months operation of this service, we surveyed hospital employees to ascertain smoking rates and views on smoking cessation in this South Australian teaching hospital. RESULTS: In the first 18 months of operation, 111 staff members availed themselves of the service. At the first follow up period (three months), 21 were not contactable, 29 were successful in not smoking and 61 were still smoking. Six of the 29 who were not smoking at three months resumed smoking by six months, and a further four resumed smoking by 12 months. At the time of this report, 12 of the remaining 19 non smokers had completed two years since quitting and a further three of these had resumed regular smoking by this time. The cost of providing the service was modest at approximately $180.00 per known successful quitter. Results from the survey showed that 12.4% of hospital employees were regular smokers. Smoking prevalence was not equally distributed with female employees being twice as likely to smoke as their male counterparts and employees in the catering department having the highest smoking prevalence (23.8%). CONCLUSIONS: Although the prevalence of cigarette smoking by employees of this teaching hospital is lower than for the general community, health sector employers can reduce smoking prevalence further by providing assistance to their employees to quit smoking. The Stop Smoking Programme we describe is effective and could be replicated by other hospitals and similar organisations.     

Effects of cocaethylene on dopamine and serotonin synthesis in Long-Evans and Sprague-Dawley brains

BACKGROUND: Primary liver cancer is an important health problem in Korea, where hepatitis B virus (HBV) infection is prevalent. The authors conducted a prospective cohort study to evaluate the protective effect of HBV vaccination against liver cancer in adults. METHODS: A total of 370,285 males aged > or = 30 comprised the study population. They were clinically free of liver diseases, and had not been vaccinated against HBV at enrolment. The results of HBV surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) marker positivity and those of the vaccination programme which took place during 1985 were used for the construction of the cohort. About 5% (n = 18,914) were HBsAg positive, 78,094 were anti-HBs positive, and 273,277 were negative for both. Among the candidates for HBV vaccination (n = 273,277), 35,934 (13.2%) people had been vaccinated against HBV during 1985. Cases of liver cancer were ascertained by record linkage and from medical records covering 1986-1989. A multivariate log-linear model was used to test statistical significance and to estimate relative risks (RR). RESULTS: The total follow-up period was 1,404,566 person-years, with an average of 3 years and 10 months. A total of 302 incident cases were ascertained. The overall incidence rate of liver cancer was 21.7 per 100,000 person-years. With reference to the incidence level among the unvaccinated and uninfected, the RR of primary liver cancer among the chronically infected and that of the unvaccinated and infected was 18.1 (95% CI: 14.2-22.9) and 0.34 (95% CI: 0.19-0.60), respectively. The RR among the vaccinated group was 0.58 (95% CI: 0.31-1.09). CONCLUSIONS: This study suggested that artificial immunization through HBV vaccination, even in adulthood, reduces the risk of liver cancer. It might also offer a practicable means of primary prevention, especially in areas with hyperendemicity of HBV infection.     

Phorbol esters increase dopamine transporter phosphorylation and decrease transport Vmax

Sodium- and chloride-coupled transport of dopamine from synapses into presynaptic terminals plays a key role in terminating dopaminergic neurotransmission. Regulation of the function of the dopamine transporter, the molecule responsible for this translocation, is thus of interest. The primary sequence of the dopamine transporter contains multiple potential phosphorylation sites, suggesting that the function of the transporter could be regulated by phosphorylation. Previous work from this laboratory has documented that phorbol ester activation of protein kinase C (PKC) decreases dopamine transport Vmax in transiently expressing COS cells. In the present report, we document in vivo phosphorylation of the rat dopamine transporter stably expressed in LLC-PK1, cells and show that phosphorylation is increased threefold by phorbol esters. Dopamine uptake is also regulated by phorbol esters in these cells; phorbol 12-myristate 13-acetate (PMA) reduces transport Vmax by 35%. Parallels between the time course, concentration dependency, and staurosporine sensitivity of alterations in transporter phosphorylation and transporter Vmax suggest that dopamine transporter phosphorylation involving PKC could contribute to this decreased transporter function. Phosphorylation of the dopamine transporter by PKC or by a PKC-activated kinase could be involved in rapid neuroadaptive processes in dopaminergic neurons.     

Increased 3-nitrotyrosine in brains of Apo E-deficient mice

Apolipoprotein E (Apo-E) is linked to the pathogenesis of Alzheimer's disease. Apo-E deficient mice have increased lipid peroxidation in plasma. In the present study we examined two markers of oxidative stress in brains of Apo-E deficient mice. The ratios of 2,3 and 2,5 dihydroxybenzoic acid (DHBA)/salicylate, an index of hydroxyl radical generation, were unchanged except for an increase in 2.5-DHBA/salicylate in the cerebellum. 3-Nitroxyrosine is a marker for nitration of proteins produced by peroxynitrite. Concentrations of 3-nitrotyrosine were significantly increased in the cerebral cortex, hippocampus, brainstem and cerebellum of Apo-E deficient mice. These results suggest the Apo-E may modulate oxidative stress produced by peroxynitrite.     

Effect of scopolamine on the efflux of dopamine and its metabolites after clozapine, haloperidol or thioridazine

The extracellular concentrations of dopamine (DA) and its metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in the striatum and the nucleus accumbens were measured in awake, freely-moving rats. Clozapine (20 mg/kg, i.p.) increased extracellular DA and HVA in both regions but increased DOPAC only in the striatum. Scopolamine (1 mg/kg), although it had no effect by itself in the striatum or nucleus accumbens, inhibited the ability of clozapine to increase extracellular DA, DOPAC and HVA concentrations in the striatum. The clozapine-induced increase in DA in the frontal cortex was not blocked by scopolamine. Haloperidol (1 mg/kg, i.p.) and thioridazine (10 mg/kg, i.p.) also increased extracellular DA, DOPAC and HVA in the striatum, but scopolamine pretreatment did not inhibit these increases. The results suggest that clozapine differs from haloperidol and thioridazine in that the effect of clozapine, but not that of the two neuroleptic drugs, to increase DA release in the striatum acutely depends on muscarinic receptor stimulation. These results suggest that clozapine, despite its strong muscarinic antagonist properties, does not produce full blockade of muscarinic receptors in vivo in the striatum. The interaction of clozapine with the cholinergic system in the striatum could be relevant to its lack of ability to produce extrapyramidal symptoms or tardive dyskinesia.     

Brain dopamine and seizure susceptibility in mice

In electroshock test apomorphine appeared without effect, D, L-amphetamine and L-DOPA (in a high dose) elevated the convulsive threshold, while amantadine decreased it. Among investigated dopamine (DA) receptor blockers spiperone, pimozide and fluphenazine lowered the threshold, haloperidol being without effect. The convulsive threshold elevated by L-DOPA was not affected by neuroleptics and phentolamine but on the other hand DA receptor blockers and phentolamine anatagonized the effect of D, L-amphetamine. The effect of amantadine was not influenced by neuroleptics. In pentylenetetrazol (PTZ) test only amantadine and L-DOPA (in high doses) affected the threshold, increasing seizure susceptibility; the above effect was not abolished by pimozide. Our results seem to indicate that the activity of brain DA system seems not to be involved directly in the susceptibility to electrogenic or PTZ-induced seizures in mice.     

Effect of vinconate on the extracellular levels of dopamine and its metabolites in the rat striatum: microdialysis studies

Multiple endocrine neoplasia type 2B/3 is characterized by multiple mucosal neuromas, a marfanoid appearance, medullary thyroid carcinoma, pheochromocytoma, gastrointestinal ganglioneuromatosis, and thickened corneal nerves. This rare syndrome is inherited in an autosomal dominant pattern. Early recognition followed by appropriate screening and treatment can be life-saving.     

Locally infused taurine, GABA and homotaurine alter differently the striatal extracellular concentrations of dopamine and its metabolites in rats

We studied in vivo the effects of locally infused taurine (50, 150, and 450 mM) on the striatal dopamine and its metabolites in comparison with those of GABA and homotaurine, a GABAA receptor agonist, in freely moving rats. The extracellular dopamine concentration was elevated maximally 2.5-, 2- and 4-fold by taurine, GABA and homotaurine, respectively. At 150 mM concentration, at which the maximum effects occurred, homotaurine increased the extracellular dopamine more than taurine or GABA. When taurine and GABA were infused simultaneously with tetrodotoxin the output of dopamine did not differ from that in the presence of tetrodotoxin alone. In comparison, tetrodotoxin did not inhibit the increase in extracellular dopamine caused by homotaurine. Furthermore, omission of calcium from the perfusion fluid inhibited the increase of extracellular dopamine caused by GABA. However, it did not block the increase of dopamine caused by taurine or homotaurine. The present study suggests that the effects of intrastriatal taurine, GABA and homotaurine on the striatal extracellular dopamine differ. Thus, these amino acids seem to affect the striatal dopaminergic neurons via more than one mechanism.     

Changes in levels of monoamines and their metabolites in incompletely ischemic brains of spontaneously hypertensive rats

In order to investigate changes in levels of monoamines and their related substances together with those of other neurotransmitters (acetylcholine and GABA), choline and substances related to energy metabolism (ATP, lactate and glucose) accompanying incomplete cerebral ischemia, a bilateral common carotid artery occlusion model of spontaneously hypertensive rats (SHR) was utilized. Animals were subjected to 1 or 2 h ischemia. Then the concentrations of substances were measured in the cerebral cortex, hippocampus and striatum and compared with control values. Due to the incomplete ischemia, ATP showed a moderate decrease, while lactate and choline increased remarkably, and GABA underwent a moderate increase. With regard to monoamines, both noradrenaline and serotonin levels were reduced in the cerebral cortex and hippocampus, whereas dopamine levels increased in the hippocampus. All monoamine metabolites, i.e. metabolites by monoamine oxidase (MAO), metabolites by catechol-O-methyltransferase (COMT), and metabolites by both MAO and COMT, underwent increases. The 3-methoxytyramine level in particular showed marked increases. Furthermore levels of precursor amino acids as well as 5-hydroxytryptophan rose. Acetylcholine decreased moderately only in the cerebral cortex. Among these changes, sustained increases in all the monoamine metabolites were characteristic of changes in the incompletely ischemic brain, suggesting that both COMT and MAO retain their activities in the incompletely ischemic brain.     

Structure-function relationship of T-2 toxin and its metabolites in inducing thymic apoptosis in vivo in mice

Recently we found that a single administration of T-2 toxin (T-2), a trichothecene mycotoxin, into mice induced DNA fragmentation, a biochemical hallmark of apoptosis, in the thymus. In this study, we investigated the effective chemical structure(s) of T-2-derived metabolites capable of inducing thymic apoptosis in vivo in mice. Metabolic conversion of T-2 to 3'-hydroxy-T-2 toxin (3'-OH-T-2) did not diminish the apoptosis-inducing activity, since essentially the same level of fragmented DNA was detected in the thymus taken from mice injected with either T-2 or 3'-OH-T-2. In contrast, hydrolysis of T-2 and 3'-OH-T-2 at the carbon-4 (C-4) position to HT-2 toxin (HT-2) and 3'-hydroxy-HT-2 toxin (3'-OH-HT-2), respectively, greatly decreased the level of DNA fragmentation. Similarly, hydrolysis of T-2 at the carbon-8 (C-8) position to neosolaniol strongly diminished its ability to induce DNA fragmentation. T-2 tetraol, having no ester groups, was unable to induce apoptosis. Based on the data presented in this study, we concluded that both the acetyl group at the C-4 position and the isovaleryl or 3'-hydroxyisovaleryl group at the C-8 position of the T-2 molecule are important for inducing cell death through apoptosis in the thymus.     

A kinetic analysis of the effects of beta-phenylethylamine on the concentrations of dopamine and its metabolites in the rat striatum

The purpose of this investigation was to determine whether the increase in the dopamine (DA) concentration in the rat striatum after a rapid iv injection of beta-phenylethylamine (PEA) can be quantitatively explained by the alteration of the striatum PEA concentration using a constructed DA metabolism model and to examine whether the time courses of the striatum DA metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) concentration can be described by this DA metabolism model. The time courses of PEA concentration in plasma and the striatum were determined by gas chromatography-mass spectrometry. The plasma PEA concentration was described by a two-compartment model with nonlinear elimination kinetics. The striatum PEA concentration was about 10 times higher than the plasma PEA concentration. The time course of the striatum PEA concentration was described by a diffusion-limited model including a Michaelis-Menten type transport system from plasma to the striatum and nonlinear elimination from the striatum. The DA concentration in the striatum increased immediately after PEA injection. In contrast, the DOPAC concentration in the striatum decreased immediately. HVA concentration in the striatum increased gradually. Assuming that the enhancement of DA concentration in the striatum after PEA injection is caused by the competitive inhibition of PEA on the reuptake of DA into DA neuronal terminals (and the metabolism from DA to DOPAC is then competitively inhibited by PEA in the DA neuronal terminals), the relationship between the enhancement of DA concentration and PEA concentration in the striatum was analyzed using a constructed DA metabolism model. The enhancement of the DA concentration in the striatum was described quantitatively by this model. Thus, it was clarified that a quantitative relationship between PEA concentration and the enhancement of DA concentration in the striatum is present after PEA injection. However, the time courses of the striatum DOPAC (lower dose) and HVA (time delay) concentrations could not be described by this model. These results indicated that other factors might be necessary to explain the time courses of the DOPAC and HVA concentrations in the striatum after PEA injection, such as the separate evaluation of the effect of PEA on the reuptake of DA into DA neuronal terminals and on the monoamine oxidase-B (MAO-B) activity in the DA neuronal terminals, and the metabolic pathway from DOPAC to HVA.     

Alterations in dopamine release but not dopamine autoreceptor function in dopamine D3 receptor mutant mice

Dopamine (DA) autoreceptors expressed along the somatodendritic extent of midbrain DA neurons modulate impulse activity, whereas those expressed at DA nerve terminals regulate both DA synthesis and release. Considerable evidence has indicated that these DA autoreceptors are of the D2 subtype of DA receptors. However, many pharmacological studies have suggested an autoreceptor role for the DA D3 receptor. This possibility was tested with mice lacking the D3 receptor as a result of gene targeting. The basal firing rates of DA neurons within both the substantia nigra and ventral tegmental area were not different in D3 receptor mutant and wild-type mice. The putative D3 receptor-selective agonist R(+)-trans-3,4,4a, 10b-tetrahydro-4-propyl-2H,5H-(1)benzopyrano(4,3-b)-1,4-oxazin+ ++-9-ol (PD 128907) was equipotent at inhibiting the activity of both populations of midbrain DA neurons in the two groups of mice. In the gamma-butyrolactone (GBL) model of DA autoreceptor function, mutant and wild-type mice were identical with respect to striatal DA synthesis and its suppression by PD 128907. In vivo microdialysis studies of DA release in ventral striatum revealed higher basal levels of extracellular DA in mutant mice but similar inhibitory effects of PD 128907 in mutant and wild-type mice. These results suggest that the effects of PD 128907 on dopamine cell function reflect stimulation of D2 as opposed to D3 receptors. Although D3 receptors do not seem to be significantly involved in DA autoreceptor function, they may participate in postsynaptically activated short-loop feedback modulation of DA release.     

Enhanced accumulation of ribavirin and its metabolites in liver versus erythrocytes in mice administered with the liver targeted drug

OBJECTIVE: Determine the frequency and relationship between ischemic heart disease (IHD) and serum cholesterol levels (SCL) in non insulin dependent diabetes mellitus (NIDDM) of the primary medical care level. MATERIAL AND METHODS: A total of 411 patients from the first medical care level were studied. The sociodemographic profile, SCL and glycemia were determined and conventional ECG was taken. The ST uneveness, ischemic T or pathological Q waves in two or more tappings was considered as IHD. Patients with history of IHD were not included. RESULTS: The male:female ratio was 1.5:1. Mean SCL was 225 mg/dl (in females 240.8 +/- 56 mg/dl and 220.7 +/- 50.7 in males). In 90 patients we identified IHD (22%), with male predominance (0.85:1, F:M). In the stratified statistical analysis the SCL > or = 200 mg/dl and IHD were significantly associated. The frequency of IHD by SCL levels of 200-239 mg/dl was 24.6% (OR 2.04; CI 95% 1.03-4.07, p = 0.04) and 24.2% (OR 1.99; CI 95% 1.02-3.96, p = 0.04) for SCL of 240-300 mg/dl; in patients with SCL > 300 mg/dl, an increase of IHD to 38.7% was observed (OR 3.95; CI 95% 1.52-10.30, p = 0.002). CONCLUSIONS: The hypercholesterolemia was one of the most important cardiovascular risk factors in NIDDM, in which SCL > or = 200 mg/dl must be considered strongly associated to IHD.     

Expression of inducible nitric oxide synthase in the brains of scrapie-infected mice

Thoracic trauma in the elderly population constitutes a major challenge for both thoracic and trauma surgeons as their presentation and outcomes differ from the adult population in addition to their high morbidity and mortality. One hundred and one patients, 60 years of age or older, with thoracic trauma were treated at Dicle University School of Medicine during a 6-year period. Eighty-five per cent were male and 15% were female with a mean age of 64.5 years. The cause of thoracic injury was blunt in 77.2% and penetrating in 22.8% of the patients. Sixty-two patients (61.4%) had isolated thoracic injuries. The median Injury Severity Score (ISS) was 23. The morbidity rate was 23.8%. The mortality rate was 16.8%. Seven of 10 patients (70%) who had an ISS greater than 25 died, whereas six of 24 (25%) patients with an ISS between 17 and 25, and four of 67 (5.9%) patients with an ISS less than 16 died. In the elderly the morbidity and mortality rates were higher for blunt trauma compared with penetrating trauma. For ISS greater than 25 the mortality rate was 71.4% for blunt and 66.6% for penetrating trauma. As the morbidity and mortality rate are significantly higher in the elderly patients the approach to these patients should include recognition of their high risk for morbidity and mortality, especially for those who had an ISS greater than 25.     

Identification of novel metabolites of butadiene monoepoxide in rats and mice

Differences in the metabolism of 1,3-butadiene (Bd) in rats and mice may account for the observed species difference in carcinogenicity. Previous studies of the metabolic fate of Bd have identified epoxide formation as a key metabolic transformation which gives 1, 2-epoxy-3-butene (BMO), although some evidence of aldehyde metabolites is reported. In this study, male Sprague-Dawley rats and male B6C3F1 mice received single doses of [4-14C]BMO at 1, 5, 20, and 50 mg/kg of body weight (0.014, 0.071, 0.286, and 0.714 mmol/kg of body weight). Analysis of urinary metabolites indicated that both species preferentially metabolize BMO by direct reaction with GSH when given by ip administration. The excretion of (R)-2-(N-acetyl-L-cystein-S-yl)-1-hydroxybut-3-ene (IIa), 1-(N-acetyl-L-cystein-S-yl)-2-(S)-hydroxybut-3-ene (IIb), 1-(N-acetyl-L-cystein-S-yl)-2-(R)-hydroxybut-3-ene (IIc), and (S)-2-(N-acetyl-L-cystein-S-yl)-1-hydroxybut-3-ene (IId) accounted for 48-64% of urinary radioactivity in rats and 46-54% in mice. The metabolites originating from the R-stereoisomer of BMO (IIc and IId) predominated over those arising from the S-stereoisomer (IIa and IIb) in both species. IIc was formed preferentially in mice and IId in rats. The corresponding mercaptoacetic acids, S-(1-hydroxybut-3-en-2-yl)mercaptoacetic acid (IIf) and S-(2-hydroxybut-3-en-1-yl)mercaptoacetic acid (IIg), were identified only in mouse urine (ca. 20% of the recovered radioactivity). 4-(N-Acetyl-L-cystein-S-yl)-1,2-dihydroxybutane (Ia), a metabolite derived from hydrolysis of BMO, accounted for 10-17% of the radioactivity in rat and 6-10% in mouse urine. 4-(N-Acetyl-L-cystein-S-yl)-2-hydroxybutanoic acid (Ib), 3-(N-acetyl-L-cystein-S-yl)propan-1-ol (Ic), and 3-(N-acetyl-L-cystein-S-yl)propanoic acid (Id), also derived from the hydrolysis of BMO, were only present in the rat. Metabolites of 1,2,3,4-diepoxybutane (DEB) were not detected after administration of BMO in rat or mouse urine. This study showed both quantitative and qualitative differences in the metabolism of BMO with varying doses and between species. The data aid in the safety evaluation of Bd and contribute to the interpretation of mathematical models developed for quantitative risk assessment and extrapolation of animals to humans.